INVITED Strings, branes, supergravity Constraining conformal field ARTICLE theories with a slightly broken Classical and and gauge theory higher spin symmetry Juan Maldacena and Alexander Zhiboedov FTC Quantum Gravity Quantum supersymmetric cosmology 2013 Class. Quantum Grav. 30 104003 and its hidden Kac-Moody structure “Determines the leading form of the correlation functions in the CFT dual for a large class of higher spin theories, using only very general properties of the T Damour and P Spindel theory. The resulting form of the correlation functions is highly constrained. Highlights of 2013–2014 2013 Class. Quantum Grav. 30 162001 These universal results will likely play an important part in the development of “This is a an elegant paper, where ingredients such as supersymmetry, group holographic duality for higher spin.” Comment from Editorial Board theory, fundamental physics, the early universe and lateral comments to other areas come together in a highly technical article that is brief but very Welcome to the 2015 CQG Highlights brochure, featuring some of the best papers informative. This work shows how quantum cosmology without supersymmetry cannot be ignored.” Comment from Editorial Board Holography without strings? published during the last 12 months, as selected by our Editorial Board. 14% Donald3.6 Marolf As the centenary of Albert Einstein’s discovery of general relativity, 2015 will be an 2014 Class. Quantum Grav. 31 015008 exciting year for the CQG community. To mark this occasion, CQG will publish a special 12% TOPICAL Double field theory: REVIEW “Emphasizes the role of the gravitational Gauus law constraint and issue of the journal entitled ‘Milestones of General Relativity’, which will review some of a pedagogical review entanglement3.4 in the bulk in holography. The discussion of Reeh-Schlieder 10% sheds an interesting new light on the reconstruction of bulk observables from the most important developments in the history of gravitational physics. You can also Gerardo Aldazabal, Diego Marqués and Carmen Núñez boundary correlators.” Comment from Editorial Board watch for the full scientific output of the Gravity Probe B mission, which will appear in 20138% Class. Quantum Grav. 30 163001 CQG in 2015. 3.2 “Double6% field theory is a field theory formulated in a configuration space with The last 12 months have been very eventful for the journal. CQG’s new companion twice the number of coordinates which incorporates T-duality in a natural FOCUS Relativistic effects in cosmology ISSUE website, CQG+ (at cqgplus.com) has generated some considerable interest. Papers way.4% It is a growing area or research and this paper provides a timely review from the basics of DFT until recent topics like its connection with gauged Guest3.0 Editors Kazuya Koyama featured on CQG+ are among the most read in the journal. It’s a great place to learn supergravity theories and flux compactifications. It is written in a very clear Upcoming galaxy surveys will probe the large-scale structures of the Universe about your peers in the community and their work in an informal setting. CQG+ has also way2% and it is very useful for beginners as well as experienced researchers in the IMPACT FACTOR on ever larger scales with ever greater precision. These surveys also probe published movie reviews, interviews, details of prizes sponsored by CQG and other news. area.” Comment from Editorial Board 0% galaxies2.8 at higher redshifts when the Hubble scale is smaller and general * Go to CQG+ and follow the site to receive instant notifications of this new and varied 2009 2010 2011 2012 2013 relativistic (GR)2007 effects become2008 more 2009important. This2010 focus issue2011 contains2012 3.103 content. a selection of articles by the authors who pioneered the development in our *As listed in the 2013 ISI Journal understanding of general relativistic effects in cosmological observations. Citation Reports® CQG made the headlines this year with the publication of a paper co-written by Kip Thorne Submissions to CQG (papers) and the visual effects team who worked on Christopher Nolan’s Interstellar. The paper More popular than ever, CQG experienced a record Focus issues can be found at details how the images of Interstellar’s black hole was created, and is freely number of regular paper submissions in 2014. iopscience.org/0264-9381/page/Focus issues available to read in CQG. Interstellar went on to win an Oscar® for best visual effects. 1000
950 Clifford M Will Editor-in-Chief, Classical and Quantum Gravity 900
850
800 The Bergmann-Wheeler Thesis Prize 750 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 This prize, sponsored by Classical and Quantum Gravity, is awarded every three years by the International Society on General Relativity and Gravitation (ISGRG) for the best PhD thesis in quantum gravity. It is named after 2 great pioneers of quantum gravity: John Wheeler and Peter Bergmann. The winner of the prize will receive $1800 and a certificate. The next prize will be awarded at the GR21 meeting in New York City in 2016. To be considered, nominations must be received by 30 September 2015. Guidelines for the nomination are available at isgrg.org
Past recipients are: 2013 Aron C Wall, thesis institution: University of Maryland 2010 Victor Taveras, thesis institution: Pennsylvania State University
Gary Horowitz President, International Society on General Relativity and Gravitation
8 Classical and Quantum Gravity: Highlights 2013–2014 iopscience.org/cqg iopscience.org/cqg Classical and Quantum Gravity: Highlights 2013–2014 1 Black holes Relativistic astrophysics Quantum gravity Hamiltonian treatment of linear field theories in the presence of boundaries: Instability of black holes in FTC Stability of charged solitons and formation A discrete, unitary, causal theory of a geometric approach massive gravity of boson stars in five-dimensional anti-de quantum gravity Fernando Barbero G, Jorge Prieto, Eduardo J S Villasenor 2014 Class. Quantum Grav. 31 045021 Eugeny Babichev and Alessandro Fabbri Sitter spacetime Aron Wall 2013 Class. Quantum Grav. 30 152001 “This paper presents a rigorous treatment of the scalar and electromagnetic Y Brihaye et al 2013 Class. Quantum Grav. 30 115002 fields in the presence of boundaries in the Hamiltonian framework. The work “Vainstein screening has played important roles in recent 2013 Class. Quantum Grav. 30 115009 “This paper shows the kind of structures need to provide a discrete and causal is based on the implementation of the geometric constraint algorithm of developments of alternative gravity theories and their applications “This paper finds a number of interesting new results for solitons and boson model of quantum gravity.” Comment from Editorial Board Gotay, Nester and Hinds. The geometric approach implemented in this paper to cosmology and astrophysics. This article is a very elegant review stars in AdS spacetime, showing that boson stars in asymptotic AdS can have provides important insights on the role of the boundaries and identification of of the subject.” Comment from Editorial Board arbitrarily large charge and mass (in contrast to the situation in asymptotically the physical degrees of freedom.” Comment from Editorial Board flat space) as well as a mass/charge gap for these kinds of solutions.” The Renormalisation group and Weyl Comment from Editorial Board The generalized second law implies Invariance Entanglement and quantum gravity FOCUS a quantum singularity theorem ISSUE A Codello, G D'Odorico, C Pagani and R Percacci Guest Editors: Eugenio Bianchi and Carlo Rovelli Dynamic and thermodynamic stability of 2013 Class. Quantum Grav. 30 115015 Aron C Wall Quantum gravity alone is not the only major theoretical open problem in 2013 Class. Quantum Grav. 30 165003 relativistic perfect fluid stars “This paper gives a modern particle physics interpretation of a very classical fundamental physics: gravity, quantum theory and thermodynamics form geometric idea due to Hermann Weyl. While Weyl’s idea in its original form was “Interesting singularity theorem where there are regions where the a triple, whose full interconnections we have definitely not yet understood. Stephen R Green, Joshua S Schiffrin, Robert M Wald not experimentally viable, it led to modern gauge theories. This paper looks semiclassical approximation is valid and using arguments based on As soon as quantum effects appear in a curved spacetime, thermal aspects 2014 Class. Quantum Grav. 31 035023 at the matter from the modern perspective of the renormalisation group and the generalized second law. A new concept of quantum trapped appear to be unavoidable. Combining thermodynamics and (full) gravity trace anomalies.” Comment from Editorial Board surface is also introduced.” Comment from Editorial Board “This paper provides a unified and comprehensive analysis of dynamic and might turn out to be even more crucial than understanding the quantum thermodynamic stability of self-gravitating perfect fluids in General Relativity aspects of the gravitational field alone. In recent years, it has become using Lagrangian methods.” Comment from Editorial Board increasingly clear that entanglement entropy is a central ingredient for the What happens at the horizon(s) of an A gravitational entropy proposal synthesis we are seeking. extreme black hole? Recent years have seen a flourishing of interest in the role that entanglement Astrophysics and general relativity FOCUS Timothy Clifton, George F R Ellis and Reza Tavakol entropy plays in the physics of spacetime. Insights have been obtained into ISSUE 2013 Class. Quantum Grav. 30 1250095 Keiju Murata, Harvey S Reall and Norihiro Tanahashi the role of entanglement for the entropy for black hole thermodynamics, and new ideas have been explored connecting entanglement to holography, 2013 Class. Quantum Grav. 30 235007 of dense stellar systems “This paper proposes a new definition of gravitational entropy based on wormholes, to the structure itself of semiclassical spacetime and others. Guest Editors: Pau Amaro-Seoane and Clifford M Will the Bel-Robinson tensor that could be applicable to cosmological settings. “By numerically solving the non-linear Einstein equations, this paper shows This special issue collects a number of articles on this topic, offering a partial Further study will be required to determine how viable this proposal is, but it that extreme black hole horizons that form dynamically exhibit an instability overview of these new developments. This focus issue on the “Astrophysics and General Relativity of Dense Stellar merits serious consideration since it connects black hole entropy to a broader on the horizon that leads to an effective singularity from the point of view of Systems’’ brings together an array of invited articles on important aspects of definition of entropy of a gravitational field.” Comment from Editorial Board observers who fall into the black hole at late times.” Comment from Editorial this question. It was inspired by a workshop on “Stellar dynamics and growth Focus issues can be found at of massive black holes’’ held in Alájar, Spain in September 2013. Most of the authors of articles in this issue were participants in that workshop. It iopscience.org/0264-9381/page/Focus issues Classical information transmission capacity is our hope that this focus issue will foster continued collaboration among The generator of spatial diffeomorphisms relativists and astrophysicists, in particular dynamicists, to address the of quantum black holes physics of dense stellar systems. in the Koslowski–Sahlmann representation Christoph Adami and Greg Ver Steeg Focus issues can be found at Madhavan Varadarajan 2014 Class. Quantum Grav. 31 075015 2013 Class. Quantum Grav. 30 175017 iopscience.org/0264-9381/page/Focus issues “Using methods from quantum information theory, these authors show that “This article addresses the issue of constructing diffeomorphism constraint black holes can stimulate emission of radiation that copies information operator in the Koslowski-Sahlmann representation in loop quantum from infalling matter whilst satisfying quantum no-cloning requirements. The gravity. This work shows that difficulties associated with the construction of implications for the information loss and firewall paradoxes are clear and diffeomorphism constraint operator using holonomy and flux operators can important.” Comment from Editorial Board be overcome by identifying new background exponential operators. A rigorous construction of the diffeomorphism constraint is provided in the enlarged Did you know? holonomy-flux-background exponential algebra. The construction is potentially Stability, instability, canonical energy All of the articles featured in this brochure are free to very useful in gaining important insights on the emergence of smooth classical read on the CQG website until 31 December 2015. geometries from the quantum geometry.” Comment from Editorial Board and charged black holes Visit iopscience.org/cqg for more information J Keir 2014 Class. Quantum Grav. 31 035014 “Establishing the existence of instabilities of black hole solutions often involves an arduous study of linearized perturbations. Recently, it has been shown that under some circumstances one can demonstrate instability simply by considering properties of perturbed initial data. This paper shows how to do this for charged black holes and thereby provides a proof of the Gubser-Mitra conjecture relating classical and thermodynamic instability of charged black branes.” Comment from Editorial Board
2 Classical and Quantum Gravity: Highlights 2013–2014 iopscience.org/cqg iopscience.org/cqg Classical and Quantum Gravity: Highlights 2013–2014 7 Cosmology Discrete Newtonian Cosmology Numerical relativity Higher-dimensional gravity G Gibbons and G Ellis TOPICAL 2014 Class. Quantum Grav. 31 025003 and other theories of gravity Multiversality REVIEW Massive disc formation in the tidal “Normally in astrophysical cosmology it is assumed that Newtonian theory F Wilczek disruption of a neutron star by a nearly adequately describes the formation of large scale structure. In this paper the FTC 2013 Class. Quantum Grav. 30 193001 authors clearly lay down a rigorous and self consistent pedagogical foundation extremal black hole Time delays across saddles “The cosmological multiverse, which is suggested in current fundamental for a purely Newtonian theory of cosmology, valid at scales small compared Geoffrey Lovelace, Matthew D Duez, Francois Foucart, Lawrence E Kidder, as a test of modified gravity theories of physics, has been much discussed in the recent scientific cosmological scales. They are thus able to justify the usual assumptions Harald P Pfeiffer, Mark A Scheel and Béla Szilágyi literature, often with a more philosophical bent. Wilczek presents a very behind the elementary standard spatially homogeneous and isotropic João Magueijo and Ali Mozaffari 2013 Class. Quantum Grav. 30 115009 readable and informative topical review on the theoretical and empirical Raychaudhuri and Friedmann equations without making any fluid dynamic or 2013 Class. Quantum Grav. 30 092002 motivations of the cosmological multiverse, and its potential “disruptive continuum approximations.” Comment from Editorial Board “Extends the simulation of black hole--neutron star mergers to a higher, but “This paper presents novel ways to test Modified Newtonian Dynamics implications for the traditional program of fundamental physics”. In particular astrophysically favored, black hole spin of 0.97. The resulting increase using the time delay effects at the saddle points of the gravitation potential he focusses on the firmly rooted and plausible inflationary axion cosmological in accretion disc and outflow mass could have important implications for where the Newtonian force vanishes and modifications to Newton gravity are paradigm, and discusses its possible testable phenomenological FTC observing electromagnetic counterparts to merger events found by LIGO and Inflationary attractors and maximised in these theories. Experiments using Lunar Laser Ranging and Very consequences.” Comment from Editorial Board Virgo.” Comment from Editorial Board their measures Large Baseline Interferometry are discussed.” Comment from Editorial Board Alejandro Corichi and David Sloan INVITED Error-analysis and comparison to analytical The Higgs field as an inflaton ARTICLE 2014 Class. Quantum Grav. 31 062001 An introduction to the INVITED models of numerical waveforms produced ARTICLE Fedor Bezrukov “An insightful work on the measure problem in the inflationary models which Vainshtein mechanism 2013 Class. Quantum Grav. 30 214001 gives significant insights on the probability for inflation to occur. This paper by the NRAR collaboration addresses some of the misconceptions in the literature. Conclusions from Eugeny Babichev and Cédric Deffayet “This is a comprehensive review on Higgs inflation in which the Higgs field of this work are significant to understand the naturalness of inflation in different I Hinder et al 2013 Class. Quantum Grav. 30 184001 the standard model can lead to the inflationary expansion of the Universe due frameworks describing the very early universe.” 2014 Class. Quantum Grav. 31 025012 to its non-minimal coupling to gravity. It summarises its predictions and also Comment from Editorial Board “An interesting paper on black holes in the context of massive gravity, showing problems related to its quantisation.” Comment from Editorial Board “A catalogue of gravitational waveforms from black-hole binaries is generated that they are always unstable, even if the instability timescale can be huge.” using different numerical codes and compared with analytical waveform Comment from Editorial Board models. The comparison highlights where further improvements of the models INVITED Backreaction and continuum limit in a are required and more numerical waveforms are needed for calibration. An Effective field theory of overview of the numerical ingredients used in numerical relativity is given and ARTICLE closed universe filled with black holes An analysis of characteristics INVITED cosmological perturbations the article provides standards for the analysis of the waveforms.” ARTICLE Mikolaj Korzynski Comment from Editorial Board in nonlinear massive gravity Federico Piazza and Filippo Vernizzi 2014 Class. Quantum Grav. 31 085002 2013 Class. Quantum Grav. 30 214007 Keisuke Izumi and Yen Chin Ong “In this paper Korzynski discusses a novel approach to a fundamental 2013 Class. Quantum Grav. 30 184008 “This review summarises the recent developments of effective theory of problem in mathematical cosmology. By considering a cosmological model Geometric boundary data for the cosmological perturbations. The effective theory considers perturbations with discrete sources (consisting of a number of black holes in vacuum), he gravitational field “This article revisits the issue of causality in nonlinear massive gravity without as the Nambu-Goldstone modes related to spontaneous breaking of time is able to quantify the coarse-grained effects of the inhomogeneities (or the the so called BD ghost. It was pointed out that the characteristics analysis translational invariance. It is now widely used both in early and late universe to cosmological backreaction) which correctly describe the properties of the H-O Kreiss and J Winicour must be performed after solving the constraint equation and that the previous study various theoretical models in a unified framework.” spacetime on macroscopic scales, and investigate the conditions under 2014 Class. Quantum Grav. 31 065004 study claiming acausality is incomplete in this respect.” Comment from Editorial Board which the physical geometry approaches the coarse-grained background Comment from Editorial Board geometry in an appropriate continuum limit. These cosmological backreaction “Interesting progress in identifying local geometric data on a timelike effects may be important in the interpretation of cosmological observations. boundary guaranteeing a well-posedness result for the initial-boundary value problem for the Einstein field equations.” Comment from Editorial Board TOPICAL But even if they are not, this analysis leads to a deeper understanding of the Loops in inflationary REVIEW cosmological model.” Comment from Editorial Board Deconstructing dimensions and correlation functions massive gravity Takahiro Tanaka and Yuko Urakawa Claudia de Rham, Andrew Matas and Andrew J Tolley 2013 Class. Quantum Grav. 30 233001 2014 Class. Quantum Grav. 31 025004 “This is an excellent review of the issue of IR divergences in correlation Did you know? “Deconstruction of gravity and multi-graviton systems were revisited in light of functions from inflation. Features common in all (adiabatic, isocurvature and CQG has an Advisory Panel of around 50 senior the recently found nonlinear interaction terms without the so called BD ghost.” tensor) types of perturbations are clarified.” Comment from Editorial Board referees who support the Editorial Board in Comment from Editorial Board maintaining the rigour and speed of peer review
CQG+ (cqgplus.com) is the companion website to Classical and Quantum Gravity, which features accessible A Birkhoff Theorem for Shape Dynamics overviews of high-quality papers published in the journal. Submit your paper to CQG to benefit from this extra Henrique Gomes promotion of your work. CQG+ 2014 Class. Quantum Grav. 31 085008 “This paper establishes the very interesting result that the spherically symmetric, asymptotically flat solution of shape dynamics corresponds to an isotropic wormhole.” Comment from Editorial Board
6 Classical and Quantum Gravity: Highlights 2013–2014 iopscience.org/cqg iopscience.org/cqg Classical and Quantum Gravity: Highlights 2013–2014 3 Experimental Gravity The stochastic background: scaling laws and Mathematical relativity Conformal Carroll groups and FTC time to detection for pulsar timing arrays BMS symmetry TOPICAL How gravitational-wave REVIEW Xavier Siemens, Justin Ellis, Fredrick Jenet and Joseph D Romano Momentum in general relativity: local versus C Duval, G W Gibbons and P A Horvathyg observations can shape the 2013 Class. Quantum Grav. 30 224015 quasilocal conservation laws 2014 Class. Quantum Grav. 31 092001 “A detailed analysis of how a stochastic gravitational-wave signal can be “Demonstrates a new relation between the BMS group (the asymptotic gamma-ray burst paradigm extracted from pulsar timing data, pointing the way to a preferred strategy, and Richard J Epp, Paul L McGrath and Robert B Mann symmetry group of an asymptotically flat spacetime) and a group arising from 2013 Class. Quantum Grav. 30 195019 I Bartos, P Brady and S Márka projecting when a signal may finally emerge from the noise.” the Poincare group in the limit of vanishing speed of light. May have important implications for recent work on the application of the BMS group to scattering 2013 Class. Quantum Grav. 30 123001 Comment from Editorial Board “This well-written paper continues a worthwhile investigation into relativistic conservation laws in conjunction with the authors’ notion of a “rigid quasilocal amplitudes.” Comment from Editorial Board “A comprehensive review interleaving the astrophysical processes and frame”. This paper represents the state of the art in this area of relativity.” gravitational-wave emission mechanisms of binary coalescences and other Method to reduce excess noise of a detuned Comment from Editorial Board likely GRB progenitors. Outlines observing strategies and the many things IOP Gravitational Physics Group Thesis Prize that can potentially be deduced from gravitational-wave observations of these cavity for application in KAGRA events.” Comment from Editorial Board The Gravitational Physics Group (GPG) Thesis Prize, sponsored by Classical Shinichiro Ueda, Nana Saito, Daniel Friedrich, Yoichi Aso and The Lichnerowicz equation on compact and Quantum Gravity, is awarded for excellence in postgraduate research Kentaro Somiya (for the KAGRA collaboration) and communication skills in gravitational physics. 2014 Class. Quantum Grav. 31 095003 manifolds with boundary A new limit on local Lorentz invariance The winner receives £500, and is invited to speak at the annual Britgrav “Discusses, with admirable clarity, the technical issues associated with Michael Holst and Gantumur Tsogtgerel meeting organised by the GPG. violation of gravity from solitary pulsars detuning signal recycling cavities in gravitational wave detectors. By showing 2013 Class. Quantum Grav. 30 205011 how technical noise can be reduced, it confirms the promise of using detuning Further information about the prize and the nomination procedure can be Lijing Shao, R Nicolas Caballero, Michael Kramer, Norbert Wex, “This article contains some results that are interesting in themselves as David J Champion and Axel Jessner to shape the frequency response of advanced detectors.” found on the GPG website: gp.iop.org Comment from Editorial Board contributing to a broader programme of work.” Comment from Editorial Board 2013 Class. Quantum Grav. 30 165019 This year’s winner of the prize was Dr Patricia Schmidt for her thesis “Continuing a program of using millisecond pulsars to reach ever tighter limits “Studying and Modelling the Complete Gravitational-Wave Signal from on post-Newtonian parameters, Shao and colleagues have constrained a Precessing Black Hole Binaries”, completed at Cardiff University under the preferred frame parameter better by a factor 100 than had been achieved in Increasing LIGO sensitivity by feedforward Non-CMC solutions of the Einstein constraint supervision of Mark Hannam. the solar system.” Comment from Editorial Board equations on asymptotically Euclidean subtraction of auxiliary length control noise Bangalore Sathyaprakash Grant David Meadors, Keita Kawabe and Keith Riles manifolds Chair 2014 Class. Quantum Grav. 31 105014 Gravitational Physics Group New limits on the violation of local position James Dilts, Jim Isenberg, Rafe Mazzeo and Caleb Meier “A very important result with real LIGO data that shows how the Michelson 2014 Class. Quantum Grav. 31 065001 invariance of gravity length control noise can be subtracted from the gravitational strain h(t) using “This article solves an open problem and has potential future applications simple feedforward substraction methods. If used, this will especially improve Lijing Shao and Norbert Wex for the construction of binary black hole initial data with non-trivial linear the advanced detectors' sensitivity in their most sensitive frequency band 2013 Class. Quantum Grav. 30 165020 momentum. This article is recommended for both mathematical and where control noises may be contributing to the overall noise floor.” numerical relativists.” Comment from Editorial Board “This paper uses observations of very stable, isolated millisecond pulsars to Comment from Editorial Board limit any precession produced by a ‘Whitehead’ term in the post-Newtonian metric. The limit on the Whitehead PPN parameter is an improvement by 6 orders of magnitude over solar-system bounds, and shows once again that FOCUS Gravitational double layers Whitehead's theory of gravity is well and truly dead.” Advanced interferometric ISSUE Comment from Editorial Board gravitational wave detectors Jose Senovilla 2014 Class. Quantum Grav. 31 072002 Guest Editors: Peter Shawhan and Marie-Anne Bizouard “This is a technical paper. It is known that gravitational double layers, unlike New method for determining the light The quest to detect gravitational waves directly has accelerated in the their classical electromagnetic counterparts, do not occur in general relativity past decade with the successful operation of a first generation of large (and are usually assumed to be unphysical). However, this paper clearly travel time in static, spherically symmetric interferometric detectors. The lessons learned from the first-generation demonstrates (using the mathematical properties of thin shells) that double spacetimes. Calculation of the terms of detectors fed into the design of advanced detectors which are now being layers do exist in some alternative, modified gravitational theories (e.g. constructed and commissioned and will soon begin collecting data. quadratic F(R) theories).” Comment from Editorial Board order G3 Higher laser power, sophisticated mirror suspensions and numerous other improvements will extend the distance reach of the detectors by an order of Bernard Linet and Pierre Teyssandier magnitude and finally record the tiny gravitational-wave signals traversing 2013 Class. Quantum Grav. 30 175008 Earth. This special issue examines the advanced techniques and detectors Axisymmetric constant mean curvature “A new method to compute the travel time of a photon in terms of the spatial currently being assembled, tested and prepared. slices in the Kerr spacetime positions of the emitter and the receiver, with an explicit calculation up to order G3. The full expression up to this order is new. The existence of enhanced Focus issues can be found at David Schinkel, Rodrigo Panosso Macedo and Marcus Ansorg terms when emitter and receiver are in conjunction is confirmed. These are iopscience.org/0264-9381/page/Focus issues 2014 Class. Quantum Grav. 31 075017 necessary to determine the post-newtonian parameter gamma with precision 10–8.” Comment from Editorial Board “This work will have applications in numerical relativity simulations and is of general interest in further understanding the Kerr solution.” Comment from Editorial Board
4 Classical and Quantum Gravity: Highlights 2013–2014 iopscience.org/cqg iopscience.org/cqg Classical and Quantum Gravity: Highlights 2013–2014 5 Experimental Gravity The stochastic background: scaling laws and Mathematical relativity Conformal Carroll groups and FTC time to detection for pulsar timing arrays BMS symmetry TOPICAL How gravitational-wave REVIEW Xavier Siemens, Justin Ellis, Fredrick Jenet and Joseph D Romano Momentum in general relativity: local versus C Duval, G W Gibbons and P A Horvathyg observations can shape the 2013 Class. Quantum Grav. 30 224015 quasilocal conservation laws 2014 Class. Quantum Grav. 31 092001 “A detailed analysis of how a stochastic gravitational-wave signal can be “Demonstrates a new relation between the BMS group (the asymptotic gamma-ray burst paradigm extracted from pulsar timing data, pointing the way to a preferred strategy, and Richard J Epp, Paul L McGrath and Robert B Mann symmetry group of an asymptotically flat spacetime) and a group arising from 2013 Class. Quantum Grav. 30 195019 I Bartos, P Brady and S Márka projecting when a signal may finally emerge from the noise.” the Poincare group in the limit of vanishing speed of light. May have important implications for recent work on the application of the BMS group to scattering 2013 Class. Quantum Grav. 30 123001 Comment from Editorial Board “This well-written paper continues a worthwhile investigation into relativistic conservation laws in conjunction with the authors’ notion of a “rigid quasilocal amplitudes.” Comment from Editorial Board “A comprehensive review interleaving the astrophysical processes and frame”. This paper represents the state of the art in this area of relativity.” gravitational-wave emission mechanisms of binary coalescences and other Method to reduce excess noise of a detuned Comment from Editorial Board likely GRB progenitors. Outlines observing strategies and the many things IOP Gravitational Physics Group Thesis Prize that can potentially be deduced from gravitational-wave observations of these cavity for application in KAGRA events.” Comment from Editorial Board The Gravitational Physics Group (GPG) Thesis Prize, sponsored by Classical Shinichiro Ueda, Nana Saito, Daniel Friedrich, Yoichi Aso and The Lichnerowicz equation on compact and Quantum Gravity, is awarded for excellence in postgraduate research Kentaro Somiya (for the KAGRA collaboration) and communication skills in gravitational physics. 2014 Class. Quantum Grav. 31 095003 manifolds with boundary A new limit on local Lorentz invariance The winner receives £500, and is invited to speak at the annual Britgrav “Discusses, with admirable clarity, the technical issues associated with Michael Holst and Gantumur Tsogtgerel meeting organised by the GPG. violation of gravity from solitary pulsars detuning signal recycling cavities in gravitational wave detectors. By showing 2013 Class. Quantum Grav. 30 205011 how technical noise can be reduced, it confirms the promise of using detuning Further information about the prize and the nomination procedure can be Lijing Shao, R Nicolas Caballero, Michael Kramer, Norbert Wex, “This article contains some results that are interesting in themselves as David J Champion and Axel Jessner to shape the frequency response of advanced detectors.” found on the GPG website: gp.iop.org Comment from Editorial Board contributing to a broader programme of work.” Comment from Editorial Board 2013 Class. Quantum Grav. 30 165019 This year’s winner of the prize was Dr Patricia Schmidt for her thesis “Continuing a program of using millisecond pulsars to reach ever tighter limits “Studying and Modelling the Complete Gravitational-Wave Signal from on post-Newtonian parameters, Shao and colleagues have constrained a Precessing Black Hole Binaries”, completed at Cardiff University under the preferred frame parameter better by a factor 100 than had been achieved in Increasing LIGO sensitivity by feedforward Non-CMC solutions of the Einstein constraint supervision of Mark Hannam. the solar system.” Comment from Editorial Board equations on asymptotically Euclidean subtraction of auxiliary length control noise Bangalore Sathyaprakash Grant David Meadors, Keita Kawabe and Keith Riles manifolds Chair 2014 Class. Quantum Grav. 31 105014 Gravitational Physics Group New limits on the violation of local position James Dilts, Jim Isenberg, Rafe Mazzeo and Caleb Meier “A very important result with real LIGO data that shows how the Michelson 2014 Class. Quantum Grav. 31 065001 invariance of gravity length control noise can be subtracted from the gravitational strain h(t) using “This article solves an open problem and has potential future applications simple feedforward substraction methods. If used, this will especially improve Lijing Shao and Norbert Wex for the construction of binary black hole initial data with non-trivial linear the advanced detectors' sensitivity in their most sensitive frequency band 2013 Class. Quantum Grav. 30 165020 momentum. This article is recommended for both mathematical and where control noises may be contributing to the overall noise floor.” numerical relativists.” Comment from Editorial Board “This paper uses observations of very stable, isolated millisecond pulsars to Comment from Editorial Board limit any precession produced by a ‘Whitehead’ term in the post-Newtonian metric. The limit on the Whitehead PPN parameter is an improvement by 6 orders of magnitude over solar-system bounds, and shows once again that FOCUS Gravitational double layers Whitehead's theory of gravity is well and truly dead.” Advanced interferometric ISSUE Comment from Editorial Board gravitational wave detectors Jose Senovilla 2014 Class. Quantum Grav. 31 072002 Guest Editors: Peter Shawhan and Marie-Anne Bizouard “This is a technical paper. It is known that gravitational double layers, unlike New method for determining the light The quest to detect gravitational waves directly has accelerated in the their classical electromagnetic counterparts, do not occur in general relativity past decade with the successful operation of a first generation of large (and are usually assumed to be unphysical). However, this paper clearly travel time in static, spherically symmetric interferometric detectors. The lessons learned from the first-generation demonstrates (using the mathematical properties of thin shells) that double spacetimes. Calculation of the terms of detectors fed into the design of advanced detectors which are now being layers do exist in some alternative, modified gravitational theories (e.g. constructed and commissioned and will soon begin collecting data. quadratic F(R) theories).” Comment from Editorial Board order G3 Higher laser power, sophisticated mirror suspensions and numerous other improvements will extend the distance reach of the detectors by an order of Bernard Linet and Pierre Teyssandier magnitude and finally record the tiny gravitational-wave signals traversing 2013 Class. Quantum Grav. 30 175008 Earth. This special issue examines the advanced techniques and detectors Axisymmetric constant mean curvature “A new method to compute the travel time of a photon in terms of the spatial currently being assembled, tested and prepared. slices in the Kerr spacetime positions of the emitter and the receiver, with an explicit calculation up to order G3. The full expression up to this order is new. The existence of enhanced Focus issues can be found at David Schinkel, Rodrigo Panosso Macedo and Marcus Ansorg terms when emitter and receiver are in conjunction is confirmed. These are iopscience.org/0264-9381/page/Focus issues 2014 Class. Quantum Grav. 31 075017 necessary to determine the post-newtonian parameter gamma with precision 10–8.” Comment from Editorial Board “This work will have applications in numerical relativity simulations and is of general interest in further understanding the Kerr solution.” Comment from Editorial Board
4 Classical and Quantum Gravity: Highlights 2013–2014 iopscience.org/cqg iopscience.org/cqg Classical and Quantum Gravity: Highlights 2013–2014 5 Cosmology Discrete Newtonian Cosmology Numerical relativity Higher-dimensional gravity G Gibbons and G Ellis TOPICAL 2014 Class. Quantum Grav. 31 025003 and other theories of gravity Multiversality REVIEW Massive disc formation in the tidal “Normally in astrophysical cosmology it is assumed that Newtonian theory F Wilczek disruption of a neutron star by a nearly adequately describes the formation of large scale structure. In this paper the FTC 2013 Class. Quantum Grav. 30 193001 authors clearly lay down a rigorous and self consistent pedagogical foundation extremal black hole Time delays across saddles “The cosmological multiverse, which is suggested in current fundamental for a purely Newtonian theory of cosmology, valid at scales small compared Geoffrey Lovelace, Matthew D Duez, Francois Foucart, Lawrence E Kidder, as a test of modified gravity theories of physics, has been much discussed in the recent scientific cosmological scales. They are thus able to justify the usual assumptions Harald P Pfeiffer, Mark A Scheel and Béla Szilágyi literature, often with a more philosophical bent. Wilczek presents a very behind the elementary standard spatially homogeneous and isotropic João Magueijo and Ali Mozaffari 2013 Class. Quantum Grav. 30 115009 readable and informative topical review on the theoretical and empirical Raychaudhuri and Friedmann equations without making any fluid dynamic or 2013 Class. Quantum Grav. 30 092002 motivations of the cosmological multiverse, and its potential “disruptive continuum approximations.” Comment from Editorial Board “Extends the simulation of black hole--neutron star mergers to a higher, but “This paper presents novel ways to test Modified Newtonian Dynamics implications for the traditional program of fundamental physics”. In particular astrophysically favored, black hole spin of 0.97. The resulting increase using the time delay effects at the saddle points of the gravitation potential he focusses on the firmly rooted and plausible inflationary axion cosmological in accretion disc and outflow mass could have important implications for where the Newtonian force vanishes and modifications to Newton gravity are paradigm, and discusses its possible testable phenomenological FTC observing electromagnetic counterparts to merger events found by LIGO and Inflationary attractors and maximised in these theories. Experiments using Lunar Laser Ranging and Very consequences.” Comment from Editorial Board Virgo.” Comment from Editorial Board their measures Large Baseline Interferometry are discussed.” Comment from Editorial Board Alejandro Corichi and David Sloan INVITED Error-analysis and comparison to analytical The Higgs field as an inflaton ARTICLE 2014 Class. Quantum Grav. 31 062001 An introduction to the INVITED models of numerical waveforms produced ARTICLE Fedor Bezrukov “An insightful work on the measure problem in the inflationary models which Vainshtein mechanism 2013 Class. Quantum Grav. 30 214001 gives significant insights on the probability for inflation to occur. This paper by the NRAR collaboration addresses some of the misconceptions in the literature. Conclusions from Eugeny Babichev and Cédric Deffayet “This is a comprehensive review on Higgs inflation in which the Higgs field of this work are significant to understand the naturalness of inflation in different I Hinder et al 2013 Class. Quantum Grav. 30 184001 the standard model can lead to the inflationary expansion of the Universe due frameworks describing the very early universe.” 2014 Class. Quantum Grav. 31 025012 to its non-minimal coupling to gravity. It summarises its predictions and also Comment from Editorial Board “An interesting paper on black holes in the context of massive gravity, showing problems related to its quantisation.” Comment from Editorial Board “A catalogue of gravitational waveforms from black-hole binaries is generated that they are always unstable, even if the instability timescale can be huge.” using different numerical codes and compared with analytical waveform Comment from Editorial Board models. The comparison highlights where further improvements of the models INVITED Backreaction and continuum limit in a are required and more numerical waveforms are needed for calibration. An Effective field theory of overview of the numerical ingredients used in numerical relativity is given and ARTICLE closed universe filled with black holes An analysis of characteristics INVITED cosmological perturbations the article provides standards for the analysis of the waveforms.” ARTICLE Mikolaj Korzynski Comment from Editorial Board in nonlinear massive gravity Federico Piazza and Filippo Vernizzi 2014 Class. Quantum Grav. 31 085002 2013 Class. Quantum Grav. 30 214007 Keisuke Izumi and Yen Chin Ong “In this paper Korzynski discusses a novel approach to a fundamental 2013 Class. Quantum Grav. 30 184008 “This review summarises the recent developments of effective theory of problem in mathematical cosmology. By considering a cosmological model Geometric boundary data for the cosmological perturbations. The effective theory considers perturbations with discrete sources (consisting of a number of black holes in vacuum), he gravitational field “This article revisits the issue of causality in nonlinear massive gravity without as the Nambu-Goldstone modes related to spontaneous breaking of time is able to quantify the coarse-grained effects of the inhomogeneities (or the the so called BD ghost. It was pointed out that the characteristics analysis translational invariance. It is now widely used both in early and late universe to cosmological backreaction) which correctly describe the properties of the H-O Kreiss and J Winicour must be performed after solving the constraint equation and that the previous study various theoretical models in a unified framework.” spacetime on macroscopic scales, and investigate the conditions under 2014 Class. Quantum Grav. 31 065004 study claiming acausality is incomplete in this respect.” Comment from Editorial Board which the physical geometry approaches the coarse-grained background Comment from Editorial Board geometry in an appropriate continuum limit. These cosmological backreaction “Interesting progress in identifying local geometric data on a timelike effects may be important in the interpretation of cosmological observations. boundary guaranteeing a well-posedness result for the initial-boundary value problem for the Einstein field equations.” Comment from Editorial Board TOPICAL But even if they are not, this analysis leads to a deeper understanding of the Loops in inflationary REVIEW cosmological model.” Comment from Editorial Board Deconstructing dimensions and correlation functions massive gravity Takahiro Tanaka and Yuko Urakawa Claudia de Rham, Andrew Matas and Andrew J Tolley 2013 Class. Quantum Grav. 30 233001 2014 Class. Quantum Grav. 31 025004 “This is an excellent review of the issue of IR divergences in correlation Did you know? “Deconstruction of gravity and multi-graviton systems were revisited in light of functions from inflation. Features common in all (adiabatic, isocurvature and CQG has an Advisory Panel of around 50 senior the recently found nonlinear interaction terms without the so called BD ghost.” tensor) types of perturbations are clarified.” Comment from Editorial Board referees who support the Editorial Board in Comment from Editorial Board maintaining the rigour and speed of peer review
CQG+ (cqgplus.com) is the companion website to Classical and Quantum Gravity, which features accessible A Birkhoff Theorem for Shape Dynamics overviews of high-quality papers published in the journal. Submit your paper to CQG to benefit from this extra Henrique Gomes promotion of your work. CQG+ 2014 Class. Quantum Grav. 31 085008 “This paper establishes the very interesting result that the spherically symmetric, asymptotically flat solution of shape dynamics corresponds to an isotropic wormhole.” Comment from Editorial Board
6 Classical and Quantum Gravity: Highlights 2013–2014 iopscience.org/cqg iopscience.org/cqg Classical and Quantum Gravity: Highlights 2013–2014 3 Black holes Relativistic astrophysics Quantum gravity Hamiltonian treatment of linear field theories in the presence of boundaries: Instability of black holes in FTC Stability of charged solitons and formation A discrete, unitary, causal theory of a geometric approach massive gravity of boson stars in five-dimensional anti-de quantum gravity Fernando Barbero G, Jorge Prieto, Eduardo J S Villasenor 2014 Class. Quantum Grav. 31 045021 Eugeny Babichev and Alessandro Fabbri Sitter spacetime Aron Wall 2013 Class. Quantum Grav. 30 152001 “This paper presents a rigorous treatment of the scalar and electromagnetic Y Brihaye et al 2013 Class. Quantum Grav. 30 115002 fields in the presence of boundaries in the Hamiltonian framework. The work “Vainstein screening has played important roles in recent 2013 Class. Quantum Grav. 30 115009 “This paper shows the kind of structures need to provide a discrete and causal is based on the implementation of the geometric constraint algorithm of developments of alternative gravity theories and their applications “This paper finds a number of interesting new results for solitons and boson model of quantum gravity.” Comment from Editorial Board Gotay, Nester and Hinds. The geometric approach implemented in this paper to cosmology and astrophysics. This article is a very elegant review stars in AdS spacetime, showing that boson stars in asymptotic AdS can have provides important insights on the role of the boundaries and identification of of the subject.” Comment from Editorial Board arbitrarily large charge and mass (in contrast to the situation in asymptotically the physical degrees of freedom.” Comment from Editorial Board flat space) as well as a mass/charge gap for these kinds of solutions.” The Renormalisation group and Weyl Comment from Editorial Board The generalized second law implies Invariance Entanglement and quantum gravity FOCUS a quantum singularity theorem ISSUE A Codello, G D'Odorico, C Pagani and R Percacci Guest Editors: Eugenio Bianchi and Carlo Rovelli Dynamic and thermodynamic stability of 2013 Class. Quantum Grav. 30 115015 Aron C Wall Quantum gravity alone is not the only major theoretical open problem in 2013 Class. Quantum Grav. 30 165003 relativistic perfect fluid stars “This paper gives a modern particle physics interpretation of a very classical fundamental physics: gravity, quantum theory and thermodynamics form geometric idea due to Hermann Weyl. While Weyl’s idea in its original form was “Interesting singularity theorem where there are regions where the a triple, whose full interconnections we have definitely not yet understood. Stephen R Green, Joshua S Schiffrin, Robert M Wald not experimentally viable, it led to modern gauge theories. This paper looks semiclassical approximation is valid and using arguments based on As soon as quantum effects appear in a curved spacetime, thermal aspects 2014 Class. Quantum Grav. 31 035023 at the matter from the modern perspective of the renormalisation group and the generalized second law. A new concept of quantum trapped appear to be unavoidable. Combining thermodynamics and (full) gravity trace anomalies.” Comment from Editorial Board surface is also introduced.” Comment from Editorial Board “This paper provides a unified and comprehensive analysis of dynamic and might turn out to be even more crucial than understanding the quantum thermodynamic stability of self-gravitating perfect fluids in General Relativity aspects of the gravitational field alone. In recent years, it has become using Lagrangian methods.” Comment from Editorial Board increasingly clear that entanglement entropy is a central ingredient for the What happens at the horizon(s) of an A gravitational entropy proposal synthesis we are seeking. extreme black hole? Recent years have seen a flourishing of interest in the role that entanglement Astrophysics and general relativity FOCUS Timothy Clifton, George F R Ellis and Reza Tavakol entropy plays in the physics of spacetime. Insights have been obtained into ISSUE 2013 Class. Quantum Grav. 30 1250095 Keiju Murata, Harvey S Reall and Norihiro Tanahashi the role of entanglement for the entropy for black hole thermodynamics, and new ideas have been explored connecting entanglement to holography, 2013 Class. Quantum Grav. 30 235007 of dense stellar systems “This paper proposes a new definition of gravitational entropy based on wormholes, to the structure itself of semiclassical spacetime and others. Guest Editors: Pau Amaro-Seoane and Clifford M Will the Bel-Robinson tensor that could be applicable to cosmological settings. “By numerically solving the non-linear Einstein equations, this paper shows This special issue collects a number of articles on this topic, offering a partial Further study will be required to determine how viable this proposal is, but it that extreme black hole horizons that form dynamically exhibit an instability overview of these new developments. This focus issue on the “Astrophysics and General Relativity of Dense Stellar merits serious consideration since it connects black hole entropy to a broader on the horizon that leads to an effective singularity from the point of view of Systems’’ brings together an array of invited articles on important aspects of definition of entropy of a gravitational field.” Comment from Editorial Board observers who fall into the black hole at late times.” Comment from Editorial this question. It was inspired by a workshop on “Stellar dynamics and growth Focus issues can be found at of massive black holes’’ held in Alájar, Spain in September 2013. Most of the authors of articles in this issue were participants in that workshop. It iopscience.org/0264-9381/page/Focus issues Classical information transmission capacity is our hope that this focus issue will foster continued collaboration among The generator of spatial diffeomorphisms relativists and astrophysicists, in particular dynamicists, to address the of quantum black holes physics of dense stellar systems. in the Koslowski–Sahlmann representation Christoph Adami and Greg Ver Steeg Focus issues can be found at Madhavan Varadarajan 2014 Class. Quantum Grav. 31 075015 2013 Class. Quantum Grav. 30 175017 iopscience.org/0264-9381/page/Focus issues “Using methods from quantum information theory, these authors show that “This article addresses the issue of constructing diffeomorphism constraint black holes can stimulate emission of radiation that copies information operator in the Koslowski-Sahlmann representation in loop quantum from infalling matter whilst satisfying quantum no-cloning requirements. The gravity. This work shows that difficulties associated with the construction of implications for the information loss and firewall paradoxes are clear and diffeomorphism constraint operator using holonomy and flux operators can important.” Comment from Editorial Board be overcome by identifying new background exponential operators. A rigorous construction of the diffeomorphism constraint is provided in the enlarged Did you know? holonomy-flux-background exponential algebra. The construction is potentially Stability, instability, canonical energy All of the articles featured in this brochure are free to very useful in gaining important insights on the emergence of smooth classical read on the CQG website until 31 December 2015. geometries from the quantum geometry.” Comment from Editorial Board and charged black holes Visit iopscience.org/cqg for more information J Keir 2014 Class. Quantum Grav. 31 035014 “Establishing the existence of instabilities of black hole solutions often involves an arduous study of linearized perturbations. Recently, it has been shown that under some circumstances one can demonstrate instability simply by considering properties of perturbed initial data. This paper shows how to do this for charged black holes and thereby provides a proof of the Gubser-Mitra conjecture relating classical and thermodynamic instability of charged black branes.” Comment from Editorial Board
2 Classical and Quantum Gravity: Highlights 2013–2014 iopscience.org/cqg iopscience.org/cqg Classical and Quantum Gravity: Highlights 2013–2014 7 INVITED Strings, branes, supergravity Constraining conformal field ARTICLE theories with a slightly broken Classical and and gauge theory higher spin symmetry Juan Maldacena and Alexander Zhiboedov FTC Quantum Gravity Quantum supersymmetric cosmology 2013 Class. Quantum Grav. 30 104003 and its hidden Kac-Moody structure “Determines the leading form of the correlation functions in the CFT dual for a large class of higher spin theories, using only very general properties of the T Damour and P Spindel theory. The resulting form of the correlation functions is highly constrained. Highlights of 2013–2014 2013 Class. Quantum Grav. 30 162001 These universal results will likely play an important part in the development of “This is a an elegant paper, where ingredients such as supersymmetry, group holographic duality for higher spin.” Comment from Editorial Board theory, fundamental physics, the early universe and lateral comments to other areas come together in a highly technical article that is brief but very Welcome to the 2015 CQG Highlights brochure, featuring some of the best papers informative. This work shows how quantum cosmology without supersymmetry cannot be ignored.” Comment from Editorial Board Holography without strings? published during the last 12 months, as selected by our Editorial Board. 14% Donald3.6 Marolf As the centenary of Albert Einstein’s discovery of general relativity, 2015 will be an 2014 Class. Quantum Grav. 31 015008 exciting year for the CQG community. To mark this occasion, CQG will publish a special 12% TOPICAL Double field theory: REVIEW “Emphasizes the role of the gravitational Gauus law constraint and issue of the journal entitled ‘Milestones of General Relativity’, which will review some of a pedagogical review entanglement3.4 in the bulk in holography. The discussion of Reeh-Schlieder 10% sheds an interesting new light on the reconstruction of bulk observables from the most important developments in the history of gravitational physics. You can also Gerardo Aldazabal, Diego Marqués and Carmen Núñez boundary correlators.” Comment from Editorial Board watch for the full scientific output of the Gravity Probe B mission, which will appear in 20138% Class. Quantum Grav. 30 163001 CQG in 2015. 3.2 “Double6% field theory is a field theory formulated in a configuration space with The last 12 months have been very eventful for the journal. CQG’s new companion twice the number of coordinates which incorporates T-duality in a natural FOCUS Relativistic effects in cosmology ISSUE website, CQG+ (at cqgplus.com) has generated some considerable interest. Papers way.4% It is a growing area or research and this paper provides a timely review from the basics of DFT until recent topics like its connection with gauged Guest3.0 Editors Kazuya Koyama featured on CQG+ are among the most read in the journal. It’s a great place to learn supergravity theories and flux compactifications. It is written in a very clear Upcoming galaxy surveys will probe the large-scale structures of the Universe about your peers in the community and their work in an informal setting. CQG+ has also way2% and it is very useful for beginners as well as experienced researchers in the IMPACT FACTOR on ever larger scales with ever greater precision. These surveys also probe published movie reviews, interviews, details of prizes sponsored by CQG and other news. area.” Comment from Editorial Board 0% galaxies2.8 at higher redshifts when the Hubble scale is smaller and general * Go to CQG+ and follow the site to receive instant notifications of this new and varied 2009 2010 2011 2012 2013 relativistic (GR)2007 effects become2008 more 2009important. This2010 focus issue2011 contains2012 3.103 content. a selection of articles by the authors who pioneered the development in our *As listed in the 2013 ISI Journal understanding of general relativistic effects in cosmological observations. Citation Reports® CQG made the headlines this year with the publication of a paper co-written by Kip Thorne Submissions to CQG (papers) and the visual effects team who worked on Christopher Nolan’s Interstellar. The paper More popular than ever, CQG experienced a record Focus issues can be found at details how the images of Interstellar’s black hole was created, and is freely number of regular paper submissions in 2014. iopscience.org/0264-9381/page/Focus issues available to read in CQG. Interstellar went on to win an Oscar® for best visual effects. 1000
950 Clifford M Will Editor-in-Chief, Classical and Quantum Gravity 900
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800 The Bergmann-Wheeler Thesis Prize 750 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 This prize, sponsored by Classical and Quantum Gravity, is awarded every three years by the International Society on General Relativity and Gravitation (ISGRG) for the best PhD thesis in quantum gravity. It is named after 2 great pioneers of quantum gravity: John Wheeler and Peter Bergmann. The winner of the prize will receive $1800 and a certificate. The next prize will be awarded at the GR21 meeting in New York City in 2016. To be considered, nominations must be received by 30 September 2015. Guidelines for the nomination are available at isgrg.org
Past recipients are: 2013 Aron C Wall, thesis institution: University of Maryland 2010 Victor Taveras, thesis institution: Pennsylvania State University
Gary Horowitz President, International Society on General Relativity and Gravitation
8 Classical and Quantum Gravity: Highlights 2013–2014 iopscience.org/cqg iopscience.org/cqg Classical and Quantum Gravity: Highlights 2013–2014 1